Loxia curvirostra

Red crossbills are being seen more often by birding enthusiasts throughout Utah. Kimberly Rousch captured this image at Pinebrook in Parleys Canyon.

Crossbills are found in conifers where they feed on evergreen seed cones.

One look at the overlapping tips of the crossbill's upper and lower mandibles immediately brings to mind a deformity of some sort. It is an adaptation that enables the crossbill to become a food sourcing specialist. Crossbills can exploit the seeds sheathed inside the cones of evergreens. The crossbill places the tips of its mandibles into the conifer cone, forcing the scales apart while its tongue scoops up the seed.

Interestingly, crossbill nestlings' mandibles are straight. They begin to cross within three weeks of fledging from the nest. Both parents feed the young while the mandible tips make the crossing transition. The young can then begin feeding themselves. Red crossbills can nest as early as January, when food supplies are abundant.

The male crossbill is red overall with dark wings that show a red edging. Its tail is short, notched and dusky black. Females are a dusky buff yellow with dark black wings. Ornithologists believe there may be as many as 12 or 13 red crossbill subspecies separated by voice, bill size and range distribution.

During the breeding season, red crossbills are found in pairs. Otherwise, they are a very gregarious flocking bird.

You are often attracted to them by their vocalizations in flight. The song is a two note series of phrases ending in a trilled warble: jitt, jitt, jitt, jitt, jiiaa-jiiaa-jiiaaaaa.

Red crossbills are monogamous. The female will incubate three or four light green or blue eggs up to 18 days. The altricial young (born naked, eyes closed and helpless) fledge within 20 days. Red crossbills may raise up to two broods per year.

Backyard bird feeders have reported red crossbills taking black oil sunflower seeds this winter.

Bill Fenimore is owner of the Layton Wild Bird Center (www.wildbird.com/layton) and author of Backyard Birds of Utah.